<template>
  <el-container>
    <!-- 头部区域 -->
    <el-header>
      <div>
        <img src="../assets/logo.png" alt="" @click="logout">
        <span>后台管理系统</span>
      </div>
      <el-button type="info" @click="logout">退出</el-button>
    </el-header>
    <!-- 页面主题区域 -->
    <el-container>
      <!-- 侧边栏 -->
      <el-aside  :width="isCollapse ? '64px' : '200px'">
        <div class="toggle-button" @click="togleCollapse">|||</div>
        <!-- 侧边栏菜单 unique-opened只展开一个子菜单 router路由跳转 default-active点击高亮 collapse是否水平折叠收起菜单 collapse-transition是否开启折叠动画-->
        <el-menu
          background-color="#333744"
          text-color="#fff"
          active-text-color="#409FFF"
          :unique-opened="opened"
          :collapse="isCollapse"
          :collapse-transition="false"
          :router="true"
          :default-active="activePath"
        >
          <!-- 一级菜单 -->
          <el-submenu :index="item.path" v-for="item in menulist" :key="item.id">
            <!-- 一级菜单模板区域 -->
            <template slot="title">
              <!-- 图标 -->
              <i :class="item.icon"></i>
              <!-- 文本 -->
              <span>{{ item.name }}</span>
            </template>
            <!-- 二级菜单模板区域 -->
            <el-menu-item :index="subItem.path" v-for="subItem in item.children" :key="subItem.id" @click="saveNavState(subItem.path)">
              <template slot="title">
                <!-- 图标 -->
                <i :class="subItem.icon"></i>
                <!-- 文本 -->
                <span>{{ subItem.name }}</span>
              </template>
            </el-menu-item>
          </el-submenu>
        </el-menu>
      </el-aside>
      <!-- 右侧内容区域 -->
      <el-main>
       <!-- 路由占位符 -->
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>

</template>

<script>
export default {
  data () {
    return {
      // 左侧菜单数据
      menulist: [],
      opened: true,
      // 是否折叠
      isCollapse: false,
      // 被激活导航地址
      activePath: '/Admin/Admin/admin'
    }
  },
  created () {
    this.getMenuList()
    this.getActivePath()
  },
  methods: {
    // 退出登录
    logout () {
      // 清除session登录token
      window.sessionStorage.clear()
      this.$router.push('/login')
    },
    // 获取所有菜单
    async getMenuList () {
      const { data: res } = await this.$http.get(this.GLOBAL.menus)
      if (res.status !== 200) {
        return this.$message.error(res.info)
      }
      this.menulist = res.data.menus
    },
    // 菜单的折叠与展开
    togleCollapse() {
      this.isCollapse = !this.isCollapse
    },
    // 保存链接的激活状态
    saveNavState(activePath) {
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath
    },
    // 刷新页面激活被选中页面
    getActivePath () {
      this.activePath = window.sessionStorage.getItem('activePath')
    }
  }
}
</script>

<style lang="less" scoped>
.el-container {
  height: 100%;
}

.el-header {
  background-color: #373f41;
  display: flex;
  justify-content: space-between;
  padding-left: 0;
  align-items: center;
  color: #fff;
  font-size: 20px;

  > div {
    display: flex;
    align-items: center;

    img {
      height: 40px;
    }

    span {
      margin-left: 15px;
    }
  }
}

.el-aside {
  background-color: #333744;

  .el-menu {
    border: none;
  }
}

.el-main {
  background-color: #eaedf1;
}

.iconfont {
  margin-right: 10px;
}

.toggle-button {
  background-color: #4A5064;
  font-size: 10px;
  line-height: 24px;
  color: #fff;
  text-align: center;
  letter-spacing: 0.2em;
  // 鼠标放上去变成小手
  cursor: pointer;
}
</style>
